4.1 Properties of Minerals



Vocabulary


Inorganic: A mineral that cannot come from minerals of something living.
Crystal: A repeating pattern of some mineral particles that from a solid.
Element: A substance made from different things.
Compounds: Two different elements combined to make one.
Mohs Hardness Scale: Ranks 10 certain elements from soft to hard.
Streak: The color of the powder of a mineral.
Luster: A term that explains how a mineral reflects light from it's surface.
Cleavage: Minerals that split easily on open surfaces.
Fracture: Describes ho0w a mineral breaks and how it looks.
Fluoroesence: Minerals that grow under ultra- violet light.

Outline


What is a mineral?

  • A mineral is a naturally occurring, inorganic solid with crystal structure and definite chemical composition
Naturally Occurring
  • Cannot be man made (glass, brick) must be naturally occurring
Inorganic
  • Mineral can't get created from materials that were part of a living thing.
Solid
  • Must be solid with definite shape/volume (particles can't flow freely in a solid)
Crystal Structure
  • Crystals are formed when pattern repeats over and over again
Definite Chemical Composition
  • Should have elements in definite proportions (that creates a compound)
    • Some minerals are pure, or not created by two elements

Identifying Minerals

  • Each mineral has its own specific properties that can identify it
Hardness
  • Mohs scale rates 1-10, softest to hardest
  • Mineral can scratch any mineral softer than it, but will be scratched by harder ones

ColorScience_psnb_4.1
  • Some minerals have more than one color, not reliable source
Streak
  • Color of mineral's powder
    • Can be measured by rubbing mineral against streak plate (unglazed tile)
      • Each mineral always has its own streak, no matter what color it is.
Luster
  • How mineral reflects light from its surface
Density
  • Measured by weight, scientists use a scale
Crystal Systems
  • All have different crystal structures
Cleavage and Fracture
  • If it splits easily along flat surface, it has cleavage
    • Depends on ho crystals and atoms are arranged, Split in different ways.
  • Minerals that don't split easily have fracture
    • rough, irregular surfaces have an uneven fracture
Special Properties
  • Some minerals have unique strange properties (magnetism, etc.)

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